Rotating machines, such as gas turbines, steam turbines, hydro-turbines, pumps and motors, rotate a rotor at predetermined speeds. To monitor the angular position of the rotor, a first sensor is disposed adjacent a keyway notch disposed in the rotor. The first sensor generates a signal indicating the position of the notch and thus the angular position of the rotor. The radial position of the rotor may also be monitored utilizing second and third sensors disposed on another plane of the rotor proximate a smooth outer surface of the rotor. The second and third sensors generate signals indicative of a radial position of the rotor.
A significant drawback with this methodology, is that there may be only one accessible portion of the rotating machine (e.g., a single plane) where sensors can be disposed for monitoring the angular position and radial position of the rotor. Further, the accessible portion of the rotating machine may comprise a portion of a rotor that contains a keyway notch or key protrusion. As a result, the second and third sensors cannot be disposed proximate a smooth outer surface of the rotor as desired for determining radial displacement of the rotor.
Accordingly, there is a need for a system and method that utilizes sensors configured to measure both an angular position and a radial position of a rotor proximate a portion of the rotor containing a keyway notch or key protrusion.